1. Field of the Invention
The present invention relates generally to the field of labelling and, more specifically, to an impression tool for manually marking tubular labels for wire coding.
2. Description of the Related Art
In certain industrial applications, it becomes necessary to mark and identify electrical control wires. For example, a number of wires from a field device may lead to a central computer or central control station and those wires at the terminal end portions must be identified according to a drawing. Thus, the drawing number or line number per drawing will carry the wire number so there is a relationship between the field wiring and the system drawings. This will enable trouble shooting in the future.
Typically, wires are marked with a sleeve-type label such as a shrink-fit tubing which is cut into small (typically 1-inch) lengths and is split axially to fit the wire size or the insulation size of the wire. The individual segments are marked by a heat typing typewriter. This type of typing is called thermal printing, whereby an operator is required to type each one of the wire numbers onto each tubular label. The heat burns the plastic black or it can be burned with an ink material to fill in the hole where burnt. These tubular labels or markers are then taken out into the field and the electrician slides each one over the respective wire. If heat shrinking is required, the electrician then applies a heat gun and thus shrinks the diameter of the wire marker down to the diameter of the wire.
The heat typing and heat shrinking processes described above are generally slow and relatively expensive. Moreover, there is a distinct disadvantage in that the typewriters cannot be taken into the field or in a rough control room where there may not be electricity.
Since the wires may come into contact with oils, acids, bases, or other chemicals, wire markers which use ink may become blurred since ink is easily dissolvable. Thus, it would be advantageous to avoid using ink when labelling wires.
A need exists for a wire marker which is simple in construction and easily to use, and avoids using exposed ink (that which is on the outer surface of a label) or thermal typing.